Wicklow County Council has shot down plans by former Anglo Irish Bank chairman Seán FitzPatrick for a new home near Greystones.
It refused planning permission for the FitzPatrick proposal after concluding that the new home had the potential to result in new and significant overlooking of neighbouring properties.
The council said overlooking concerns arose particularly from the proposed home's first-floor terraces and their proximity to the boundary.
In refusing permission, the council said the planned home "would be contrary to the amenities" of those neighbouring properties.
It refused planning permission in spite of Mr FitzPatrick and his wife, Catriona, last month lodging revised plans to overcome the council's privacy concerns.
The planning authority refused planning after one neighbour who objected, Fintan Graham, told the council that it was with regret "that I find the resubmitted plans fail to address the significant impact of the build on the privacy and consequent negative impact on the amenities of our adjoining property".
In a letter dated July 10 last, Mr Graham, the owner of The Spinney, stated rough calculations indicated that at least 86pc of his garden would be overlooked from a balcony proposed for the new FitzPatrick home.
The council planner in the case said she was not satisfied that the revised plans adequately addressed the council's concerns with respect to the potential impact of the proposed development on the amenities of adjoining properties.
The council refused planning in spite of planning consultant for Mr FitzPatrick, Kevin Hughes of Hughes Planning and Development Consultants, arguing in his submission to the council that "the appropriately scaled development will not give rise to any undue impacts on the amenity of any adjacent properties".
Mr FitzPatrick now has the option of appealing the decision to An Bord Pleanála.